Letters will be sent to pupils who get good GCSE grades, offering them vital tips on how to apply for degree courses during the sixth-form, it emerged.

The letters – signed by ministers from the Department for Business, Innovation and Skills and the Department for Education – will be primarily aimed at pupils from poor backgrounds who are significantly less likely to progress onto higher education at the age of 18.

It is thought that ministers could target pupils who gain A and B grades in academic subjects that are seen as the best route to gaining a university place.

Mr Willetts said the letter would probably be sent for the first time this summer, although data protection legislation means that it would have to go via schools rather than directly to individual pupils.

The disclosure comes after the publication of research last month that suggested students from state schools were a third less likely to apply to elite Russell Group universities than those in the private sector.

Speaking at the Higher Education Funding Council for England annual conference in London, Mr Willetts said: "The starting point is some kind of letter that could indeed have been from me and an education minister saying 'congratulations Joe, congratulations Gemma, you've done really well in your GCSEs, have you thought about going to university? This is how you could set about it, here's a great website to visit and some information'."

He suggested that one possibility would be to write to schools where less than 20 per cent of students go on to higher education.

It will be seen as a criticism of schools in poor communities which are significantly less likely to send pupils onto university than those with middle-class catchment areas.

Mr Willetts said it was likely that the messages would be aimed at students that have done well in key academic GCSEs, achieving top grades.

This would have to be "more than just English and maths", he said.

"It clearly has to be the range of GCSEs that in turn lead on into the facilitating A-levels," he added.

Mr Willetts insisted that ministers would be unlikely to name specific universities, or groups of institutions.

"It would be hard to get into naming specific universities or specific mission groups, but certainly the sense that universities come in different shapes and sizes and you need to look at websites to find information about universities that are particularly suitable for your interests, I think we will want to signal that," he said.

Meanwhile, in separate comments, Mr Willetts raised concerns that some students believed they were not getting value-for-money from degree courses following a sharp rise in tuition fees.

English universities can now charge up to £9,000-a-year for a full-time course – almost three times the previous cap.

But Mr Willetts said many students complained that lecture and seminar sizes were too big and they had to wait weeks for essays to be marked.

"I think universities should not be complacent,” he said. “They are getting extra cash coming in, it needs to be spent on the highest quality level of academic student experience and I was signalling very clearly that things like class size matter."

Universities could be required to publish new data on average lecture sizes, he signalled.

Mr Willetts added: "When I sit around with groups of students in the student union it's things like 'I will send in an essay and it's weeks before I get the essay back' or 'the seminars are so crowded I'm not always able to pursue my query about the point I don't understand' or 'I'm worried that not many people on this course seem actually to end up in the kind of jobs I thought you'd get from doing this course'.”